my r button wont work and i had my ds lite for a long time now so can i fix it or do i give it to nintendo or do i have to get a new one?

Ask Gamestop to see what's the problem. I'm not that good with a DS, so I wouldn't know. I would take to Gamestop though.

whats ecactly wrong with it?

It's happened to me, and it basically just doesn't work without pressing really hard. Unlike the other button, L, which clicks then pops out after, it is like there is something stuck underneath. I sent it to Gamestation where I got it, they took it off me for a day, then said they could send it to Nintendo for me. So they did, and 4 weeks later I got it back, with a new stylus (chewed a little), and new L and R buttons. The model has been cleaned very well too.

It's clearly fixable, just ask the people where you got it from.

- James